JPH08282982A - Deflection correcting device in lift device - Google Patents

Abstract

PURPOSE: To correct deflection of a jig table so that high accurately positioning a lift position of a workpiece can be performed, by applying force to a link in a direction of extending it by an assist cylinder when lifted the jig table to a lift end position. CONSTITUTION: A jig table 3 is lifted by a lift mechanism 2 to a lift position where the second slider 27 comes into contact with a stopper 26c. Here, by weight of an automobile body W, since an end part of the jig table 3 is deflected downward, when a condition is left as it is, lift positioning accuracy of the automobile body W is generated rough. Then by supplying an air pressure to an assist cylinder 44 in a direction of contracting it, a link 4 is given force in a direction of extending it by the cylinder 44. In this way, the link 4 is extended straight while pressing an end part of the jig table 3, to come into contact with stoppers 42a, 43a, and deflection in an end part of the jig table 3 is corrected, to accurately perform positioning of the automobile body W in a prescribed lift position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending correction device in a lifting device for lifting and lowering a jig table for positioning and supporting a work with respect to a base.

[0002]

2. Description of the Related Art Conventionally, in an automobile body assembly line, an X
It is common practice to position and support a vehicle body, which is a work, on a jig table that is lifted by a lifting mechanism such as a mold link mechanism, and lift the vehicle body to a fixed position by raising the jig table and perform welding by a welding robot in general. I am trying.

[0003]

In a jig table that supports a large and heavy work piece such as an automobile body, both ends of the jig table bend downward due to the weight of the work piece, and it is not possible to strictly secure the ascending positioning accuracy of the work piece. It will be difficult. When performing a welding operation on a work, there is no particular problem because the error can be absorbed by the equalizing operation of the welding gun even if the work is lifted and positioned with high accuracy.

By the way, recently, the position of each part of the work is measured by an optical measuring head attached to the robot to measure the assembly accuracy of the work. In this case, the work is caused by the bending of the jig table. If an error occurs in the ascending position of, the measurement accuracy cannot be secured. If the deflection is constant, it can be dealt with by correcting the measurement value, but since the deflection changes depending on the model of the work, it is difficult to correct the measurement value.

In view of the above points, the present invention provides a bending correction device for an elevating device that corrects the bending of the jig table so that the rising position of the work can be positioned with high accuracy. Has an aim.

[0006]

In order to achieve the above object,
The present invention relates to an elevating device for elevating a jig table that positions and supports a work with respect to a machine base, and folds the middle between the end of the jig table and the base as the jig table descends. A flexible link is provided, and when at least one of the base and the jig table extends at a rising end position of the jig table, the link extends to a state of correcting the bending of the end of the jig table. It is characterized in that a stopper with which the ring contacts is provided and an assist cylinder that bends and extends the link is provided.

[0007]

When the jig table is raised to the rising end position, the assist cylinder applies a force to the link in a direction to extend the link. According to this, the link extends while pushing up the end of the jig table and abuts against the stopper, and the bending of the end of the jig table is corrected. Thus, the work is accurately positioned at the predetermined elevated position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an elevating device provided at a measuring station of an automobile body W which is a work. The elevating device is a jig table 3 by an elevating mechanism 2 provided on a base 1.
Is configured to move up and down.

As shown in FIGS. 1 and 2, the jig table 3 has a first positioning member including a positioning pin 30a fitted in a reference hole of a front side frame of an automobile body W and a clamper 30b for clamping the front side frame. The second positioning member 31 includes a member 30, a positioning pin that fits in a reference hole at the lower end of the front pillar portion of the automobile body W, and a positioning pin that fits in a reference hole at the lower end of the rear pillar portion of the automobile body W. , A, B, C, three third positioning members 32, and a fourth positioning member 33, which is a positioning pin that fits into a reference hole in the tail portion of the automobile body W, are provided. Position and support the car body W.

Here, the positioning position by the first positioning member 30 (front side frame reference hole) and the positioning position by the second positioning member 31 (front pillar reference hole) are common to all models, but are determined by the third positioning member 32. The position of the positioning portion (rear pillar reference hole) and the position of the fourth positioning member 33 (tail reference hole) vary depending on the model. Therefore, the A, B, and C third positioning members 32 are each made upright and undulating by the cylinder 32a, and only the positioning member 32 corresponding to the model is raised.
Further, the position of the C positioning member 32 can be adjusted back and forth by the cylinder 32b, and the position of the fourth positioning member 33 can be adjusted back and forth, left and right, and up and down by the drive mechanism 33a, so that a model change can be dealt with.

The lifting mechanism 2 includes a pair of first and second links 20, 21 pivotally connected to each other in the middle, and the first link 20.
It is composed of two sets of left and right X-shaped link mechanisms including a cylinder 22 for rocking the jig table 3, and the jig table 3 is raised by rocking the first link 20 upward by the cylinder 22. As shown in FIGS. 3 and 4, the first link 20
Is supported at its lower end by a bracket 23 fixed to the machine base 1 via a shaft 20a, and fixed to the jig table 3 by a first slider 25 engaged with a longitudinal guide rail 24. It is pivotally supported at the upper end via a shaft 20b. The second link 21 is pivotally supported by a second slider 27, which is fixed to the machine base 1 and is engaged with a longitudinal guide frame 26 in the front-rear direction, via a shaft 21a at the lower end and is fixed at the upper end. A bracket 28 fixed to the tool table 3 is pivotally supported via a shaft 21b. The guide frame 26 includes a pair of upper and lower rails 26a and 26b. The front and rear ends of the second slider 27 have rollers 27a that come into contact with the upper rail 26a from below, and a lower rail 2a.
Roller 27b that contacts 6b from above, and upper rail 26
A roller 27c that abuts from the inside in the lateral direction is attached to a, and the second slider 27 moves the guide frame 2 by these rollers.
It was designed to be smoothly moved back and forth along the line 6. Further, a stopper 26c is provided at the rear end of the guide frame 26 so that the stopper 2
The ascending of the jig table 3 is restricted by the contact of the second slider 27 with 6c. In the figure, reference numeral 29 is a synchronization bar that connects the left and right second sliders 27.

Between the jig table 3 and the machine base 1, the jig table 3 is positioned at each end in the longitudinal direction,
A pair of left and right links 4 are provided. The link 4 is
A pair of upper and lower link pieces 40, 41 pivotally attached to each other at their ends
As shown in FIG. 5, the upper end of the upper link piece 40 is attached to the bracket 42 fixed to the jig table 3 by the shaft 40.
The lower end of the lower link piece 41 is also pivotally supported on the bracket 43 fixed to the machine base 1 via the shaft 41a while the lower end of the jig table 3 is lowered.
The link 4 is bent at the connecting node 4a between the end portions of 1. In addition, an assist cylinder 44 composed of a double-acting air cylinder that bends and extends the link 4 is provided, and each stopper 42a, 43 with which each link piece 40, 41 comes into contact with each bracket 42, 43 when the link 4 extends straight.
a is provided. The left and right links 4 and 4 are connected via the synchronization bar 45 in the lower link piece 41 of each link 4 and are bent and extended in synchronization with each other.

Although not shown in the figure, robots are arranged on the left and right outer sides of the elevating device at the measuring station, and the position of each part of the automobile body is measured by an optical measuring head attached to the operating end of the robot. To be done. Further, in this embodiment, a pair of front and rear crossbars 5 and 5 are provided laterally on the jig table 3 in the vicinity of the arrangement portion of the link 4, and a total of the center and the left and right ends is provided on each crossbar 5. Three mark members 5a are erected, and each mark member 5a is set by an optical measuring head.
Is measured so that the robot coordinates for measurement can be set based on the jig table 3.

Next, the operation of the above embodiment will be described. First, the vehicle body W is carried into a measuring station by a transfer device (not shown) and transferred to the jig table 3 in the lowered position as shown in FIG. 1 (A). At this time, the vehicle body W is positioned and supported by the positioning members 30 to 33 on the jig table 3.

Then, the jig table 3 is lifted by the lifting mechanism 2.
Is raised to a raised position where the second slider 27 contacts the stopper 26c. At this time, the jig table 3 is bent by its weight due to the weight of the automobile body W, so that the ascending / positioning accuracy of the automobile body W becomes rough as it is. Therefore, air pressure is supplied to the assist cylinder 44 in the direction of contracting it, and the cylinder 44 applies a force in the direction of expanding the link 4 to the link 4. According to this,
As shown in FIG. 1 (B), the link 4 pushes up the end of the jig table 3 and straightly extends to stop the stoppers 42a and 43a.
And the bending of the end of the jig table 3 is corrected,
The vehicle body W is accurately positioned at a predetermined raised position.

Then, the operation of the robot moves the optical measuring head to a plurality of measurement points on the automobile body W in order to face each other, and measures the position of each point to measure the assembly accuracy of the automobile body W. . Prior to this measurement, it is desirable to measure the position of the gauge point member 5a at the end of the crossbar 5 to confirm whether or not the bending of the end of the jig table 3 has been corrected.

After the measurement is completed, the jig table 3 is lowered and the automobile body W is carried out from the measuring station by the transfer device. In this case, in order to prevent the lowering of the jig table 3 from the rising end position by the link 4, air pressure is supplied to the assist cylinder 44 in a direction to extend it, and force is applied to the link 4 in a direction to bend it in the middle. Is given. Although air pressure in the contracting direction or the expanding direction may be constantly supplied to the assist cylinder 44 when the jig table 3 is raised or lowered, air is supplied only after the jig table 3 is raised or when the jig table 3 is lowered. You may do it.

Although the embodiment in which the present invention is applied to the lifting device arranged in the measuring station of the automobile body W has been described above, the present invention is of course also applied to the lifting device for a work station for performing work such as welding on a work. it can. Further, when the X-type link mechanism as in the above-described embodiment is used as the lifting mechanism 2, the first slider 2 associated with the rise of the jig table 3 is used.
The movement of 5 shortens the support span of the jig table 3,
Since the end portion of the jig table 3 is easily bent, the correction of the bending by the link 4 effectively functions, but the present invention can be similarly applied to a lifting device using a lifting mechanism other than the X-shaped link.

[0019]

As is apparent from the above description, according to the present invention, since the bending of the end portion of the jig table can be corrected, the rising position of the work can be positioned with high accuracy.
Since the bending is corrected by a simple broken link, the structure is simple and the cost is low.

[Brief description of drawings]

FIG. 1A is a side view of an example of the device of the present invention in a lowered state, and FIG. 1B is a side view of the raised state.

FIG. 2 is a plan view of a jig table.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a sectional view taken along the line IV-IV of FIG.

FIG. 5 is a sectional view taken along the line VV of FIG.

[Explanation of symbols]

W Car Body (Work), 1 Machine Stand 2 Lifting Mechanism, 3 Jig Table 4 Link, 42a, 43a Stopper 44 Assist Cylinder

Claims (1)

[Claims] 1. An elevating device for elevating and lowering a jig table for positioning and supporting a work with respect to a machine base, and folding the jig table between the end of the jig table and the base as the jig table descends. When a flexible link is installed and the link extends to at least one of the base and the jig table at the rising end position of the jig table to correct the bending of the end of the jig table. A bending correction device in an elevating device, characterized in that a stopper for contacting the ring is provided on the base and an assist cylinder for bending and extending the link is provided.